net/rxrpc/output.c

   1 /* RxRPC packet transmission
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/net.h>
  15 #include <linux/gfp.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/export.h>
  18 #include <net/sock.h>
  19 #include <net/af_rxrpc.h>
  20 #include "ar-internal.h"
  21
  22 struct rxrpc_ack_buffer {
  23         struct rxrpc_wire_header whdr;
  24         struct rxrpc_ackpacket ack;
  25         u8 acks[255];
  26         u8 pad[3];
  27         struct rxrpc_ackinfo ackinfo;
  28 };
  29
  30 struct rxrpc_abort_buffer {
  31         struct rxrpc_wire_header whdr;
  32         __be32 abort_code;
  33 };
  34
  35 /*
  36  * Fill out an ACK packet.
  37  */
  38 static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
  39                                  struct rxrpc_ack_buffer *pkt,
  40                                  rxrpc_seq_t *_hard_ack,
  41                                  rxrpc_seq_t *_top,
  42                                  u8 reason)
  43 {
  44         rxrpc_serial_t serial;
  45         rxrpc_seq_t hard_ack, top, seq;
  46         int ix;
  47         u32 mtu, jmax;
  48         u8 *ackp = pkt->acks;
  49
  50         /* Barrier against rxrpc_input_data(). */
  51         serial = call->ackr_serial;
  52         hard_ack = READ_ONCE(call->rx_hard_ack);
  53         top = smp_load_acquire(&call->rx_top);
  54         *_hard_ack = hard_ack;
  55         *_top = top;
  56
  57         pkt->ack.bufferSpace    = htons(8);
  58         pkt->ack.maxSkew        = htons(call->ackr_skew);
  59         pkt->ack.firstPacket    = htonl(hard_ack + 1);
  60         pkt->ack.previousPacket = htonl(call->ackr_prev_seq);
  61         pkt->ack.serial         = htonl(serial);
  62         pkt->ack.reason         = reason;
  63         pkt->ack.nAcks          = top - hard_ack;
  64
  65         if (reason == RXRPC_ACK_PING)
  66                 pkt->whdr.flags |= RXRPC_REQUEST_ACK;
  67
  68         if (after(top, hard_ack)) {
  69                 seq = hard_ack + 1;
  70                 do {
  71                         ix = seq & RXRPC_RXTX_BUFF_MASK;
  72                         if (call->rxtx_buffer[ix])
  73                                 *ackp++ = RXRPC_ACK_TYPE_ACK;
  74                         else
  75                                 *ackp++ = RXRPC_ACK_TYPE_NACK;
  76                         seq++;
  77                 } while (before_eq(seq, top));
  78         }
  79
  80         mtu = call->conn->params.peer->if_mtu;
  81         mtu -= call->conn->params.peer->hdrsize;
  82         jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
  83         pkt->ackinfo.rxMTU      = htonl(rxrpc_rx_mtu);
  84         pkt->ackinfo.maxMTU     = htonl(mtu);
  85         pkt->ackinfo.rwind      = htonl(call->rx_winsize);
  86         pkt->ackinfo.jumbo_max  = htonl(jmax);
  87
  88         *ackp++ = 0;
  89         *ackp++ = 0;
  90         *ackp++ = 0;
  91         return top - hard_ack + 3;
  92 }
  93
  94 /*
  95  * Send an ACK call packet.
  96  */
  97 int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping)
  98 {
  99         struct rxrpc_connection *conn = NULL;
 100         struct rxrpc_ack_buffer *pkt;
 101         struct msghdr msg;
 102         struct kvec iov[2];
 103         rxrpc_serial_t serial;
 104         rxrpc_seq_t hard_ack, top;
 105         size_t len, n;
 106         int ret;
 107         u8 reason;
 108
 109         spin_lock_bh(&call->lock);
 110         if (call->conn)
 111                 conn = rxrpc_get_connection_maybe(call->conn);
 112         spin_unlock_bh(&call->lock);
 113         if (!conn)
 114                 return -ECONNRESET;
 115
 116         pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 117         if (!pkt) {
 118                 rxrpc_put_connection(conn);
 119                 return -ENOMEM;
 120         }
 121
 122         msg.msg_name    = &call->peer->srx.transport;
 123         msg.msg_namelen = call->peer->srx.transport_len;
 124         msg.msg_control = NULL;
 125         msg.msg_controllen = 0;
 126         msg.msg_flags   = 0;
 127
 128         pkt->whdr.epoch         = htonl(conn->proto.epoch);
 129         pkt->whdr.cid           = htonl(call->cid);
 130         pkt->whdr.callNumber    = htonl(call->call_id);
 131         pkt->whdr.seq           = 0;
 132         pkt->whdr.type          = RXRPC_PACKET_TYPE_ACK;
 133         pkt->whdr.flags         = RXRPC_SLOW_START_OK | conn->out_clientflag;
 134         pkt->whdr.userStatus    = 0;
 135         pkt->whdr.securityIndex = call->security_ix;
 136         pkt->whdr._rsvd         = 0;
 137         pkt->whdr.serviceId     = htons(call->service_id);
 138
 139         spin_lock_bh(&call->lock);
 140         if (ping) {
 141                 reason = RXRPC_ACK_PING;
 142         } else {
 143                 reason = call->ackr_reason;
 144                 if (!call->ackr_reason) {
 145                         spin_unlock_bh(&call->lock);
 146                         ret = 0;
 147                         goto out;
 148                 }
 149                 call->ackr_reason = 0;
 150         }
 151         n = rxrpc_fill_out_ack(call, pkt, &hard_ack, &top, reason);
 152
 153         spin_unlock_bh(&call->lock);
 154
 155         iov[0].iov_base = pkt;
 156         iov[0].iov_len  = sizeof(pkt->whdr) + sizeof(pkt->ack) + n;
 157         iov[1].iov_base = &pkt->ackinfo;
 158         iov[1].iov_len  = sizeof(pkt->ackinfo);
 159         len = iov[0].iov_len + iov[1].iov_len;
 160
 161         serial = atomic_inc_return(&conn->serial);
 162         pkt->whdr.serial = htonl(serial);
 163         trace_rxrpc_tx_ack(call, serial,
 164                            ntohl(pkt->ack.firstPacket),
 165                            ntohl(pkt->ack.serial),
 166                            pkt->ack.reason, pkt->ack.nAcks);
 167
 168         if (ping) {
 169                 call->ping_serial = serial;
 170                 smp_wmb();
 171                 /* We need to stick a time in before we send the packet in case
 172                  * the reply gets back before kernel_sendmsg() completes - but
 173                  * asking UDP to send the packet can take a relatively long
 174                  * time, so we update the time after, on the assumption that
 175                  * the packet transmission is more likely to happen towards the
 176                  * end of the kernel_sendmsg() call.
 177                  */
 178                 call->ping_time = ktime_get_real();
 179                 set_bit(RXRPC_CALL_PINGING, &call->flags);
 180                 trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_ping, serial);
 181         }
 182
 183         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
 184         if (ping)
 185                 call->ping_time = ktime_get_real();
 186
 187         if (call->state < RXRPC_CALL_COMPLETE) {
 188                 if (ret < 0) {
 189                         if (ping)
 190                                 clear_bit(RXRPC_CALL_PINGING, &call->flags);
 191                         rxrpc_propose_ACK(call, pkt->ack.reason,
 192                                           ntohs(pkt->ack.maxSkew),
 193                                           ntohl(pkt->ack.serial),
 194                                           true, true,
 195                                           rxrpc_propose_ack_retry_tx);
 196                 } else {
 197                         spin_lock_bh(&call->lock);
 198                         if (after(hard_ack, call->ackr_consumed))
 199                                 call->ackr_consumed = hard_ack;
 200                         if (after(top, call->ackr_seen))
 201                                 call->ackr_seen = top;
 202                         spin_unlock_bh(&call->lock);
 203                 }
 204         }
 205
 206 out:
 207         rxrpc_put_connection(conn);
 208         kfree(pkt);
 209         return ret;
 210 }
 211
 212 /*
 213  * Send an ABORT call packet.
 214  */
 215 int rxrpc_send_abort_packet(struct rxrpc_call *call)
 216 {
 217         struct rxrpc_connection *conn = NULL;
 218         struct rxrpc_abort_buffer pkt;
 219         struct msghdr msg;
 220         struct kvec iov[1];
 221         rxrpc_serial_t serial;
 222         int ret;
 223
 224         spin_lock_bh(&call->lock);
 225         if (call->conn)
 226                 conn = rxrpc_get_connection_maybe(call->conn);
 227         spin_unlock_bh(&call->lock);
 228         if (!conn)
 229                 return -ECONNRESET;
 230
 231         msg.msg_name    = &call->peer->srx.transport;
 232         msg.msg_namelen = call->peer->srx.transport_len;
 233         msg.msg_control = NULL;
 234         msg.msg_controllen = 0;
 235         msg.msg_flags   = 0;
 236
 237         pkt.whdr.epoch          = htonl(conn->proto.epoch);
 238         pkt.whdr.cid            = htonl(call->cid);
 239         pkt.whdr.callNumber     = htonl(call->call_id);
 240         pkt.whdr.seq            = 0;
 241         pkt.whdr.type           = RXRPC_PACKET_TYPE_ABORT;
 242         pkt.whdr.flags          = conn->out_clientflag;
 243         pkt.whdr.userStatus     = 0;
 244         pkt.whdr.securityIndex  = call->security_ix;
 245         pkt.whdr._rsvd          = 0;
 246         pkt.whdr.serviceId      = htons(call->service_id);
 247         pkt.abort_code          = htonl(call->abort_code);
 248
 249         iov[0].iov_base = &pkt;
 250         iov[0].iov_len  = sizeof(pkt);
 251
 252         serial = atomic_inc_return(&conn->serial);
 253         pkt.whdr.serial = htonl(serial);
 254
 255         ret = kernel_sendmsg(conn->params.local->socket,
 256                              &msg, iov, 1, sizeof(pkt));
 257
 258         rxrpc_put_connection(conn);
 259         return ret;
 260 }
 261
 262 /*
 263  * send a packet through the transport endpoint
 264  */
 265 int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
 266                            bool retrans)
 267 {
 268         struct rxrpc_connection *conn = call->conn;
 269         struct rxrpc_wire_header whdr;
 270         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 271         struct msghdr msg;
 272         struct kvec iov[2];
 273         rxrpc_serial_t serial;
 274         size_t len;
 275         bool lost = false;
 276         int ret, opt;
 277
 278         _enter(",{%d}", skb->len);
 279
 280         /* Each transmission of a Tx packet needs a new serial number */
 281         serial = atomic_inc_return(&conn->serial);
 282
 283         whdr.epoch      = htonl(conn->proto.epoch);
 284         whdr.cid        = htonl(call->cid);
 285         whdr.callNumber = htonl(call->call_id);
 286         whdr.seq        = htonl(sp->hdr.seq);
 287         whdr.serial     = htonl(serial);
 288         whdr.type       = RXRPC_PACKET_TYPE_DATA;
 289         whdr.flags      = sp->hdr.flags;
 290         whdr.userStatus = 0;
 291         whdr.securityIndex = call->security_ix;
 292         whdr._rsvd      = htons(sp->hdr._rsvd);
 293         whdr.serviceId  = htons(call->service_id);
 294
 295         iov[0].iov_base = &whdr;
 296         iov[0].iov_len = sizeof(whdr);
 297         iov[1].iov_base = skb->head;
 298         iov[1].iov_len = skb->len;
 299         len = iov[0].iov_len + iov[1].iov_len;
 300
 301         msg.msg_name = &call->peer->srx.transport;
 302         msg.msg_namelen = call->peer->srx.transport_len;
 303         msg.msg_control = NULL;
 304         msg.msg_controllen = 0;
 305         msg.msg_flags = 0;
 306
 307         /* If our RTT cache needs working on, request an ACK.  Also request
 308          * ACKs if a DATA packet appears to have been lost.
 309          */
 310         if (!(sp->hdr.flags & RXRPC_LAST_PACKET) &&
 311             (retrans ||
 312              call->cong_mode == RXRPC_CALL_SLOW_START ||
 313              (call->peer->rtt_usage < 3 && sp->hdr.seq & 1) ||
 314              ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
 315                           ktime_get_real())))
 316                 whdr.flags |= RXRPC_REQUEST_ACK;
 317
 318         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
 319                 static int lose;
 320                 if ((lose++ & 7) == 7) {
 321                         ret = 0;
 322                         lost = true;
 323                         goto done;
 324                 }
 325         }
 326
 327         _proto("Tx DATA %%%u { #%u }", serial, sp->hdr.seq);
 328
 329         /* send the packet with the don't fragment bit set if we currently
 330          * think it's small enough */
 331         if (iov[1].iov_len >= call->peer->maxdata)
 332                 goto send_fragmentable;
 333
 334         down_read(&conn->params.local->defrag_sem);
 335         /* send the packet by UDP
 336          * - returns -EMSGSIZE if UDP would have to fragment the packet
 337          *   to go out of the interface
 338          *   - in which case, we'll have processed the ICMP error
 339          *     message and update the peer record
 340          */
 341         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
 342
 343         up_read(&conn->params.local->defrag_sem);
 344         if (ret == -EMSGSIZE)
 345                 goto send_fragmentable;
 346
 347 done:
 348         trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags,
 349                             retrans, lost);
 350         if (ret >= 0) {
 351                 ktime_t now = ktime_get_real();
 352                 skb->tstamp = now;
 353                 smp_wmb();
 354                 sp->hdr.serial = serial;
 355                 if (whdr.flags & RXRPC_REQUEST_ACK) {
 356                         call->peer->rtt_last_req = now;
 357                         trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
 358                 }
 359         }
 360         _leave(" = %d [%u]", ret, call->peer->maxdata);
 361         return ret;
 362
 363 send_fragmentable:
 364         /* attempt to send this message with fragmentation enabled */
 365         _debug("send fragment");
 366
 367         down_write(&conn->params.local->defrag_sem);
 368
 369         switch (conn->params.local->srx.transport.family) {
 370         case AF_INET:
 371                 opt = IP_PMTUDISC_DONT;
 372                 ret = kernel_setsockopt(conn->params.local->socket,
 373                                         SOL_IP, IP_MTU_DISCOVER,
 374                                         (char *)&opt, sizeof(opt));
 375                 if (ret == 0) {
 376                         ret = kernel_sendmsg(conn->params.local->socket, &msg,
 377                                              iov, 2, len);
 378
 379                         opt = IP_PMTUDISC_DO;
 380                         kernel_setsockopt(conn->params.local->socket, SOL_IP,
 381                                           IP_MTU_DISCOVER,
 382                                           (char *)&opt, sizeof(opt));
 383                 }
 384                 break;
 385
 386 #ifdef CONFIG_AF_RXRPC_IPV6
 387         case AF_INET6:
 388                 opt = IPV6_PMTUDISC_DONT;
 389                 ret = kernel_setsockopt(conn->params.local->socket,
 390                                         SOL_IPV6, IPV6_MTU_DISCOVER,
 391                                         (char *)&opt, sizeof(opt));
 392                 if (ret == 0) {
 393                         ret = kernel_sendmsg(conn->params.local->socket, &msg,
 394                                              iov, 1, iov[0].iov_len);
 395
 396                         opt = IPV6_PMTUDISC_DO;
 397                         kernel_setsockopt(conn->params.local->socket,
 398                                           SOL_IPV6, IPV6_MTU_DISCOVER,
 399                                           (char *)&opt, sizeof(opt));
 400                 }
 401                 break;
 402 #endif
 403         }
 404
 405         up_write(&conn->params.local->defrag_sem);
 406         goto done;
 407 }
 408
 409 /*
 410  * reject packets through the local endpoint
 411  */
 412 void rxrpc_reject_packets(struct rxrpc_local *local)
 413 {
 414         struct sockaddr_rxrpc srx;
 415         struct rxrpc_skb_priv *sp;
 416         struct rxrpc_wire_header whdr;
 417         struct sk_buff *skb;
 418         struct msghdr msg;
 419         struct kvec iov[2];
 420         size_t size;
 421         __be32 code;
 422
 423         _enter("%d", local->debug_id);
 424
 425         iov[0].iov_base = &whdr;
 426         iov[0].iov_len = sizeof(whdr);
 427         iov[1].iov_base = &code;
 428         iov[1].iov_len = sizeof(code);
 429         size = sizeof(whdr) + sizeof(code);
 430
 431         msg.msg_name = &srx.transport;
 432         msg.msg_control = NULL;
 433         msg.msg_controllen = 0;
 434         msg.msg_flags = 0;
 435
 436         memset(&whdr, 0, sizeof(whdr));
 437         whdr.type = RXRPC_PACKET_TYPE_ABORT;
 438
 439         while ((skb = skb_dequeue(&local->reject_queue))) {
 440                 rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
 441                 sp = rxrpc_skb(skb);
 442
 443                 if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
 444                         msg.msg_namelen = srx.transport_len;
 445
 446                         code = htonl(skb->priority);
 447
 448                         whdr.epoch      = htonl(sp->hdr.epoch);
 449                         whdr.cid        = htonl(sp->hdr.cid);
 450                         whdr.callNumber = htonl(sp->hdr.callNumber);
 451                         whdr.serviceId  = htons(sp->hdr.serviceId);
 452                         whdr.flags      = sp->hdr.flags;
 453                         whdr.flags      ^= RXRPC_CLIENT_INITIATED;
 454                         whdr.flags      &= RXRPC_CLIENT_INITIATED;
 455
 456                         kernel_sendmsg(local->socket, &msg, iov, 2, size);
 457                 }
 458
 459                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 460         }
 461
 462         _leave("");
 463 }